JP4112352B2 - Car navigation system - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an in-vehicle navigation device that guides a vehicle to a destination along a guidance route, and in particular, an in-vehicle navigation device that changes processing contents performed by a control unit of the navigation device when the vehicle approaches a guide point such as an intersection. About.
[0002]
[Prior art]
The in-vehicle navigation device is a map data storage device such as a DVD (Digital Versatile Disk) on which map data is recorded, a display device, a gyro, a GPS (Global Positioning System) receiver, a vehicle speed sensor, and the current position of the vehicle. It has a vehicle position detection device that detects the direction. Then, map data including the current position of the vehicle is read from the map data storage device, a map image around the current position of the vehicle is drawn based on the map data, and a vehicle position mark (location) is superimposed on the map image. You can see at a glance where the vehicle is currently traveling by scrolling the map image as the vehicle moves, or by fixing the map image to the screen and moving the vehicle position mark. I have to.
[0003]
In general, the in-vehicle navigation device is equipped with a route guidance function that allows the user to easily travel to a desired destination without making a mistake on the road. According to this route guidance function, the lowest cost route connecting from the starting point to the destination using map data is automatically searched by performing simulation calculation such as horizontal search method or Dijkstra method, and the searched route is guided. Remember as a route. And when the guide route is drawn thickly on the map image with a different color from other roads and displayed on the screen, or when the vehicle approaches an intersection where the route on the guide route should be changed within a certain distance, the map The user is guided to the destination by drawing an arrow indicating the course at the intersection where the course should be changed on the image and displaying it on the screen.
[0004]
Cost is based on distance, road width, road type (general road or highway, etc.), a value multiplied by a constant according to right turn and left turn, etc., estimated travel time of vehicle, etc. The degree of appropriateness as a numerical value.
[0005]
In a general vehicle-mounted navigation device, when a vehicle is traveling along a guidance route, when an intersection that should turn right or left is approached to a predetermined distance (for example, 300 m), an enlarged view including the intersection (hereinafter, referred to as an intersection) An enlarged view of the intersection) is displayed so that a facility (landmark) that is a landmark in the vicinity of the intersection can be easily identified (for example, JP 2001-324344 A (Patent Document 1)). A vehicle position mark is also displayed on the enlarged view of the intersection, and the vehicle position mark is moved along with the movement of the vehicle so that the position of the vehicle can be grasped in more detail.
[0006]
[Patent Document 1]
JP 2001-324344 A [Patent Document 2]
JP-A-8-68651 gazette
[Problems to be solved by the invention]
Currently, the position detection accuracy of a GPS receiver mounted on a vehicle-mounted navigation device is about 10 m. In addition, in-vehicle navigation devices further improve the accuracy of the vehicle position by using a sensor such as a gyroscope and a vehicle speed sensor and a technique called map matching.
[0008]
However, in the conventional in-vehicle navigation device, although the vehicle has reached the intersection, the vehicle has not reached the intersection or the vehicle has not reached the intersection on the enlarged enlarged view of the intersection. Nevertheless, the vehicle may be displayed as if it has reached the intersection on the enlarged intersection view. In particular, where there are many narrow alleys such as in the city center, there may be other intersections immediately before or immediately before the intersection to turn left and right, which causes the user to make a mistake in the route.
[0009]
Japanese Patent Laid-Open No. 8-68651 (Patent Document 2) discloses a vehicle current position detection device that detects a speed vector and corrects an error of a current position caused by a time delay caused by a GPS positioning position averaging process. Are listed. In addition, this publication also describes obtaining an estimated position in consideration of acceleration motion.
[0010]
However, in the conventional in-vehicle navigation device, the process of determining the current position of the vehicle (current position determination process) is executed at regular intervals based on the outputs of the GPS receiver, the gyroscope, the vehicle speed sensor, and the like. Also in the vehicle current position detection device described in Japanese Patent Application Laid-Open No. 8-68651, when the speed or direction of the vehicle changes abruptly, the difference between the actual position of the vehicle and the position obtained by calculation increases. End up.
[0011]
As described above, an object of the present invention is to provide an in-vehicle navigation device that improves the positional accuracy of a vehicle on a map image and enables more accurate route guidance when the vehicle approaches a guidance point such as an intersection. It is to be.
[0012]
[Means for Solving the Problems]
The above-described problems include map data storage means for storing map data, position detection means for detecting the current position of the vehicle, map image generation means for generating a map image based on the map data, and the map image generation means Display means for displaying the map image generated in step (b), and a current position determination process for determining a current position of the vehicle based on an output of the position detection means every predetermined time, and displayed on the display means And a control unit that displays a first vehicle position mark indicating a current position of the vehicle on a map image. When the vehicle approaches a guidance point, the control unit performs the current position determination process. This is solved by an in-vehicle navigation device characterized by shortening the execution interval.
[0013]
In order to obtain the current position of the vehicle more accurately, it is conceivable to shorten the execution interval of the current position determination process. However, since the microcomputer in the navigation apparatus performs not only the current position determination process but also the map image rewriting process and various signal transmission / reception processes, the execution interval of the current position determination process is simply shortened. Then, other processing will be delayed.
[0014]
Therefore, in the present invention, the execution time of the current position determination process is shortened only when the vehicle approaches the guidance point to a predetermined distance. For example, assuming that the current position of the vehicle is determined based on the output of the position detection means every 100 milliseconds during normal travel, when the vehicle approaches the guide point, the current position of the vehicle is determined based on the output of the position detection means every 50 milliseconds. Determine the current position of the vehicle. As a result, the current position of the vehicle is more accurately displayed on the map image, and the user can accurately grasp the guidance point. In addition, for example, when the vehicle turns right or left at the intersection, the speed of the vehicle is slow and there is almost no need to rewrite the map image. Therefore, even if the current position determination processing is executed preferentially, other processing may be hindered. Is small.
[0015]
The process for determining the current position of the vehicle based on the output of the position detection means takes a certain time. For this reason, it is conceivable that a deviation occurs between the current position of the vehicle determined by the control means and the current position of the actual vehicle. In this case, the current position of the vehicle can be obtained more accurately by correcting the current position of the vehicle determined based on the output of the position detection means in accordance with the speed and acceleration of the vehicle.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.
[0017]
FIG. 1 is a block diagram showing a configuration of an in-vehicle navigation device according to an embodiment of the present invention.
[0018]
Reference numeral 1 denotes a DVD storing map data and the like. Map data stored on DVD1 is divided into longitude and latitude widths of appropriate size according to the scale level such as 1/12500, 1/25000, 1/50000, and 1/100000, etc. Is recorded as a coordinate set of vertices (nodes) expressed in longitude and latitude. A road is formed by connecting two or more nodes, and a portion connecting two nodes is called a link. The map data includes (1) a road layer composed of a road list, a node table, an intersection configuration node list, etc., (2) a background layer for displaying roads, buildings, parks, rivers, etc. on the map screen, (3 ) Consists of characters such as administrative division names such as city names, road names, intersection names, building names, and character / symbol layers for displaying map symbols.
[0019]
Reference numeral 3 denotes an operation unit provided with various operation buttons and the like for operating the navigation apparatus body 10 to be described later. Reference numeral 4 denotes a VICS receiver that receives a VICS (road traffic information communication system) signal transmitted from a radio wave beacon or an optical beacon.
[0020]
Reference numeral 5 denotes a GPS receiver that receives a GPS signal sent from a GPS satellite and detects the longitude and latitude of the current position of the vehicle. Reference numeral 6 denotes a self-contained navigation sensor, and the self-contained navigation sensor 6 includes an angle sensor 6a such as a gyro sensor or an acceleration sensor that detects a vehicle rotation angle, and a travel distance sensor 6b that generates a pulse at every constant travel distance. Has been.
[0021]
Reference numeral 7 denotes a display device such as a liquid crystal panel. The navigation device body 10 displays a map around the current position of the vehicle and various guidance information on the display device 7. Reference numeral 9 denotes a speaker for providing guidance to the user by voice.
[0022]
The navigation device body 10 is composed of the following. Reference numeral 11 denotes a DVD controller that reads data from the DVD 1. 13 is an interface connected to the operation unit 3, 14 is an interface connected to the VICS receiver 4, 15 is an interface connected to the GPS receiver 5, and 16 is an interface connected to the self-contained navigation sensor 6.
[0023]
Reference numeral 17 denotes a buffer memory that temporarily stores map data read from the DVD 1. Reference numeral 18 denotes a control unit constituted by a microcomputer. The control unit 18 detects the current position of the vehicle based on information input from the interfaces 15 and 16, reads predetermined map data from the DVD 1 to the buffer memory 17 via the DVD controller 11, Various processes such as searching for a guidance route under search conditions set using the read map data are executed.
[0024]
19 is a map drawing unit that generates a map image using the map data read to the buffer memory 17, and 21 is an operation screen / mark for generating various menu screens (operation screens), vehicle position marks, etc. according to the operation status. It is a generation part.
[0025]
Reference numeral 22 denotes a guidance route storage unit that stores the guidance route searched by the control unit 18, and reference numeral 23 denotes a guidance route drawing unit that draws the guidance route. In the guide route storage unit 22, all nodes of the guide route searched by the control unit 18 are recorded from the departure point to the destination. For example, when displaying a map, the guide route drawing unit 23 reads the guide route information (node sequence) from the guide route storage unit 22 and draws the guide route with a color and line width different from those of other roads.
[0026]
An audio output unit 24 supplies an audio signal to the speaker 9 based on a signal from the control unit 18.
[0027]
Reference numeral 25 denotes an image composition unit. For example, the map image drawn by the map drawing unit 19 is overlaid with various marks and operation screens generated by the operation screen / mark generation unit 21, the guidance route drawn by the guidance route drawing unit 23, and the like. In addition, they are displayed on the display device 7.
[0028]
In the vehicle-mounted navigation device configured as described above, the control unit 18 detects the current position of the vehicle from the GPS signal received by the GPS receiver 5 and the signal input from the self-contained navigation sensor 6. Then, map data around the current position of the vehicle is read from the DVD 1 and stored in the buffer memory 17. The map drawing unit 19 generates a map image based on the map data read to the buffer memory 17 and displays a map image around the current position of the vehicle on the display device 7.
[0029]
The control unit 18 detects the current position of the vehicle based on signals input from the GPS receiver 5 and the self-contained navigation sensor 6 as the vehicle moves, and the map displayed on the display device 7 according to the detection result. The vehicle position mark is superimposed on the image, the vehicle position mark is moved with the movement of the vehicle, or the map image is scroll-displayed. Further, when the user operates the operation unit 3 to set the destination, the control unit 18 uses the current position of the vehicle as the starting point, and uses the map data on the DVD 1 for the route with the lowest cost from the starting point to the destination. To explore. Then, the route obtained by the search is stored in the guidance route storage unit 22 as a guidance route, and the guidance route is superimposed on the map image and displayed. In addition, the control unit 18 appropriately outputs guidance information as the vehicle travels, and guides the vehicle to travel along the guidance route to the destination.
[0030]
Hereinafter, in the vehicle-mounted navigation device described above, the operation when the vehicle approaches the intersection (guide point) that should turn left and right on the guidance route will be described with reference to the flowchart shown in FIG.
[0031]
In step S11, while the vehicle is traveling along the guidance route, the control unit 18 sets the execution interval of the current position determination process to 100 milliseconds. For example, the microcomputer constituting the control unit 18 generates an interrupt every 100 milliseconds, inputs signals from the GPS receiver 5 and the self-contained navigation sensor 6, and calculates and determines the current position of the vehicle. Then, the drawing position of the vehicle position mark is determined based on the calculation result, and the vehicle position mark is displayed on the map image drawn by the map drawing unit 19 by controlling the operation screen / mark generating unit 21 as shown in FIG. 31 (first vehicle position mark) is superimposed and displayed on the display device 7. Usually, the vehicle position mark 31 is displayed near the center of the screen, and the map image is scrolled as the vehicle moves.
[0032]
Thereafter, the process proceeds to step S12, and the control unit 18 monitors whether or not the vehicle has approached an intersection to be turned left or right up to a predetermined distance (for example, 300 m). Then, when the vehicle approaches a predetermined distance to the intersection where the vehicle should turn left or right, the control unit 18 inputs map data in the vicinity of the intersection from the buffer memory 17 and transmits the map data to the operation screen / mark generation unit 21. The operation screen / mark generation unit 21 generates an enlarged intersection map based on the map data input via the control unit 18. As shown in FIG. 4, the enlarged view of the intersection is displayed on the display device 7 by being superimposed on the map image drawn by the map drawing unit 19. In FIG. 4, a map image 32 around the current position of the vehicle is displayed on the left side of the screen, and an enlarged intersection view 33 is displayed on the right side. Further, the vehicle current position mark 31 is displayed on the map image 32, and the vehicle current position mark 31a (second vehicle position mark) is displayed on the intersection enlarged view 33.
[0033]
Next, the process proceeds to step S14, and the control unit 18 sets the execution interval of the current position determination process to 50 milliseconds. As a result, the microcomputer constituting the control unit 18 is interrupted every 50 milliseconds, and signals from the GPS receiver 5 and the self-contained navigation sensor 6 are input to calculate the current position of the vehicle.
[0034]
The vehicle moves between the start and end of this calculation, and an error occurs between the calculated value and the actual vehicle position. In order to reduce the error, in this embodiment, the speed or acceleration (deceleration) of the vehicle is detected, and the moving distance of the vehicle until the calculation is completed is calculated. For example, if the time from the start of the current position determination process to the update of the position of the vehicle position mark is t, the vehicle speed is v, and the vehicle acceleration is a, the distance L that the vehicle moves during time t is , L = vt + (at ² ) / 2. Thus, when the speed and acceleration of the vehicle are obtained, the current position of the vehicle can be displayed more accurately. The speed and acceleration of the vehicle may be calculated from the output of the self-contained navigation sensor 6, or a sensor that detects the speed and acceleration may be provided.
[0035]
Note that a plurality of processes (tasks) are simultaneously executed in the microcomputer, and it is conceivable that if the execution interval of the position determination process is shortened, the execution of other processes is affected. However, while the vehicle turns right and left at the intersection, the speed of the vehicle is slow and there is almost no need to rewrite the map image. Therefore, even if the current position determination process is executed preferentially, there is a possibility that other processes may be hindered. small. However, by reducing the priority of processing that is not so important (or increasing the priority of the current position determination processing) while the intersection enlarged view 33 is displayed, such as VICS reception processing and map drawing processing, It is preferable to reduce the load on the computer.
[0036]
Thereafter, the process proceeds to step S15, and the control unit 18 monitors whether or not the vehicle has passed the intersection. When it is determined that the vehicle has passed the intersection, the process proceeds to step S16, and the display of the enlarged intersection view 33 is terminated. Thereafter, the process proceeds to step S17, and the control unit 18 returns the execution interval of the current position determination process to 100 milliseconds. Also, priorities such as VICS information reception processing and map drawing processing are restored.
[0037]
In the present embodiment, the position accuracy of the vehicle is temporarily improved by shortening the execution interval of the current position determination process only while the enlarged intersection map 33 is displayed. As a result, the display position of the second vehicle position mark 31a on the enlarged intersection map 33 and the actual vehicle position correspond more accurately, so that there is another intersection in the vicinity of the intersection to be turned left or right. However, it is possible to correctly guide the user along the guidance route.
[0038]
Further, in the present embodiment, the vehicle position is corrected based on the vehicle speed and acceleration only while the intersection enlarged view 33 is displayed, so the accuracy of the display position of the vehicle position mark (the actual vehicle current) Correspondence with position) is further improved.
[0039]
Furthermore, in the present embodiment, the priority of the VICS information reception process and the map drawing process is temporarily lowered only while the intersection enlarged view 33 is displayed, so that the load on the microcomputer is reduced.
[0040]
In the above embodiment, the case where the guidance point is an intersection has been described. However, the present invention can be applied even when the guidance point is a three-dimensional intersection, a route value, a destination, or the like. In the above embodiment, the execution interval of the current position determination process while displaying the enlarged intersection map 33 is 50 milliseconds, but the execution interval of the current position determination process is set according to the processing capability of the microcomputer. It may be set to 20 milliseconds or less. Furthermore, in the above embodiment, when the vehicle approaches the guidance point, the case where the intersection enlarged view 33 is displayed on the display device 7 together with the map image 32 has been described. However, the map image 32 is displayed without displaying the intersection enlarged view 33. May be displayed. In this case, by shortening the execution interval of the current position determination process, the display position of the first vehicle position mark 31 on the map image 32 and the actual vehicle position correspond more accurately.
[0041]
【The invention's effect】
As described above, according to the in-vehicle navigation device of the present invention, when the vehicle approaches the guidance point to a predetermined distance, the execution time of the current position determination process is shortened, so that the current position of the vehicle is more accurately mapped. Can be displayed on the image. Thereby, the user can grasp | ascertain a guidance point correctly, and it is avoided that a vehicle remove | deviates from a guidance route.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a configuration of an in-vehicle navigation device according to an embodiment of the present invention.
FIG. 2 is a flowchart illustrating an operation of the in-vehicle navigation device according to the embodiment when the vehicle approaches an intersection to be turned left or right on the guidance route.
FIG. 3 is a diagram illustrating a display example of a map image of the in-vehicle navigation device according to the embodiment.
FIG. 4 is a diagram illustrating a display example of an enlarged intersection view of the in-vehicle navigation device according to the embodiment.
[Explanation of symbols]
1 ... DVD,
3 ... operation part,
4 ... VICS receiver,
5 ... GPS receiver,
6 ... Self-contained navigation sensor,
7 ... display device,
9 ... Speaker,
10 ... navigation device body,
11 ... DVD controller 17 ... buffer memory,
18 ... control unit,
19 ... Map drawing part,
21 ... Operation screen / mark generator,
22 ... guide route storage unit,
23: Guide route drawing unit,
24. Audio output unit,
25: Image composition unit.

Claims (5)

Map data storage means for storing map data;
Position detecting means for detecting the current position of the vehicle;
Map image generation means for generating a map image based on the map data;
Display means for displaying the map image generated by the map image generation means;
A first vehicle position that executes a current position determination process for determining a current position of the vehicle based on an output of the position detection means at predetermined time intervals and indicates the current position of the vehicle on the map image displayed on the display means In a navigation device having a control means for displaying a mark,
The vehicle-mounted navigation device, wherein the control means shortens an execution interval of the current position determination process when the vehicle approaches a guidance point to a predetermined distance. When the vehicle approaches the guide point, the control means displays an enlarged view of the guide point and a second vehicle position mark indicating the current position of the vehicle on the enlarged view on the display means. The in-vehicle navigation device according to claim 1. The control means determines the current position of the vehicle determined based on the signal from the position detection means, the time required from the start of the current position determination process to the display of the second vehicle position mark, the speed of the vehicle, The in-vehicle navigation device according to claim 2, wherein the correction is made according to acceleration. The in-vehicle system according to claim 2, wherein the control means sets the priority of the current position determination process relatively higher than other processes while displaying an enlarged view of the guide point. Navigation device. 3. The vehicle-mounted navigation according to claim 2, wherein when the vehicle passes the guide point, the control unit stops displaying the enlarged view and restores an execution interval of the current position determination process. 4. apparatus.

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